This invention relates to a microencapsulated oil product, and to a method of making a microencapsulated oil product. More particularly, this invention relates to a microencapsulated structured lipid oil and that can be used as a vehicle for incorporating the structured lipid as a nutrient in a consumable food or beverage product. This invention also relates to consumable food and beverage products incorporating such microencapsulated structured lipids, and methods for their manufacture.
In recent years it has been learned that certain edible oil compositions can provide certain health benefits to consumers. Examples of more healthful oil compositions are disclosed in U.S. application Ser. No. 795,843, filed Mar. 8, 2004, published Sep. 8, 2005 publication number 20050196512, the disclosure of which is incorporated herein by reference in its entirety. That application discloses products that can be used in place of, or in combination with, conventional edible oil products such as domestic oils or tropical oils. The disclosed products are compositions of specially constructed edible oils in combination with a phytosterol ester component. The products have as a principal component a structured lipid which is a product of the interesterification of an edible domestic oil triglyceride and a medium chain triglyceride. These structured lipids can be combined with phytosterol esters into so-called healthful oil compositions. When desired, these compositions can be formulated with components of a type typically included within compositions for a selected intended use.
Another such healthful oil composition is described in co-pending application Ser. No. 357,162, filed Mar. 14, 2006. That application discloses a structured lipid that is a product of the interesterification of an edible domestic oil triglyceride, a medium chain triglyceride, and a conjugated linoleic acid. These structured lipids optionally can be combined with phytosterol esters into so-called healthful oil compositions. When desired, these compositions can be formulated with components of a type typically included for a selected intended use. Such oil compositions comprise an interesterified structured lipid component; the structured lipid component being a reaction product of an interesterification reactant charge, said reactant charge comprising (i) an amount of a medium chain triglyceride having fatty acid chains from C6 to C12 in length, (ii) an amount of a long chain domestic oil having fatty acid chains of at least C16 in length, and (iii) an amount of one or more isomers of conjugated linoleic acid. The oil composition optionally comprises a phytosterol ester component, and optionally one or more other edible oils.
It would be desirable to incorporate such healthful oil compositions in food and beverage products so as to impart health benefits to the consumer. Yet the use of such oil products in their liquid state could impart an unacceptable oiliness to the finished food or beverage product. Such products also could have decreased shelf-life due to the lower oxidative stability of highly unsaturated fatty acids such as those found in conjugated linoleic acid (CLA). It would thus be desirable to provide such an oil product in a for that could be added to a food or beverage product without imparting an oily quality to the food or beverage, but that would nonetheless be biologically available to the consumer when the food or beverage product is consumed.
Microencapsulation of oils is known in the art of edible oils. Microencapsulation is the coating of a liquid or solid with a protective wall material that inhibits volatilization and protects against chemical deterioration. The solid or liquid contained within the wall material is known as the core, and the complete microencapsulated particle is known as a microcapsule. Microencapsulation of oil is used to protect the oil from oxygen, water, and light, as well as to convert the oil into a free-flowing powder that can be readily incorporated into various foods. Typically, food components contained inside microcapsules are released as the food is consumed or during a food preparation step. Release of the core material is achieved by destroying the integrity of the microcapsule shell. This can be accomplished by dissolving the shell in water, melting it, or rupturing it with mechanical force. Wall materials that have been used for the microencapsulation of oil include gum arabic, carboxymethyl cellulose, alginate, gelatin, whey protein, sodium caseinate, and soy protein.
Physical processes for the microencapsulation of food ingredients use mechanical means to cause the entrapment of the core by wall materials. Typical physical methods include spray drying, air suspension coating, spray cooling and chilling, co-crystallization, and centrifugal extrusion. Microencapsulation techniques involving both physical and chemical techniques include coacervation, liposome entrapment, and inclusion complexation. Selection of the microencapsulation technique used for a particular process will depend on the economics of the different processes, the size of the microcapsules desired, the physical and chemical properties of the core and coating, the applications of the microcapsule as a food ingredient, and the desired mechanism for release of the core material.
Coacervation is a microencapsulation technique whereby the wall material is separated out of solution and deposits around the insoluble core material to form a coacervate phase. In simple coacervation, one polymer, typically a protein such as gelatin, is used to form the coacervate. The protein is first dissolved in water and a hydrophobic core material is mixed into the solution. At a neutral pH, the protein molecules will be open. As the pH is lowered, the protein molecules close up and surround droplets of the core material, thus forming microcapsules. In complex coacervation, two water soluble polymers, one cationic and one anionic, are reacted to form a microcapsule wall around a hydrophobic wall material. Typically, gelatin is used as the cationic polymer and gum arabic is used as the anionic polymer. Complex coacervation has been used to microeneapsulate oil in multiple layers of wall material.
U.S. Pat. No. 2,800,457 is a basic patent in the field disclosing the use of complex coacervation in the manufacture of oil-containing microcapsules.
U.S. Pat. No. 2,876,160 discloses a method of embedding a water-insoluble material in a starch matrix.
U.S. Pat. No. 3,786,123 discloses a method for microencapsulating a nutrient in which a mixture of the nutrient and an encapsulating agent is treated at elevated temperatures and pressures.
U.S. Pat. No. 4,217,370 discloses a process for making lipid-containing foodstuffs comprising solubilizing a particulate proteinaceous matter, admixing a lipid material to form an emulsion, and lowering the pH to aggregate the protein and simultaneously microencapsulate the lipid.
U.S. Pat. No. 4,908,233 discloses a hydrous composition containing an electrolyte and microcapsules coated with a water-soluble polymer which undergoes phase separation by action of the electrolyte.
U.S. Pat. No. 4,921,705 discloses a lipid powder with a cross-linked coating prepared by emulsifying the lipid and a water-soluble protein-containing coating agent, adding a cross-linking agent to cross-link the protein, atomizing and drying the emulsion to terminate the cross-linking reaction and to obtain lipid powders each coated with the water-soluble coating agent, and cooling the lipid powders.
U.S. Pat. No. 5,051,304 discloses microcapsules made by complex coacervation with gelatin and certain polysaccharides.
U.S. Pat. No. 5,456,985 discloses microcapsules of an oily liquid in which the coating material comprises a gastro-resistant polymer, which can be a protein, the microcapsules made by atomization of an oil-in-water emulsion of the oily liquid and an aqueous solution comprising the gastro-resistant polymer and an emulsifier. The preferred polymer is cellulose acetylphthalate.
U.S. Pat. No. 5,601,760 discloses a method for microencapsulation of a volatile or non-volatile core material such an oil in a wall system consisting essentially of a whey protein. The microcapsules are typically made by spray drying.
U.S. Pat. No. 6,149,953 discloses microcapsules comprising a core surrounded by a shell, the shell having seeding agents disposed therein to impart enhanced or unique structural and/or functional characteristics.
U.S. Pat. No. 6,475,542 and U.S. Pat. No. 6,592,916 disclose microcapsules comprising a core of an edible hydrophobic substance, and a capsule wall formed by the salting-out of a combination of a protein and an edible salt, and transglutaminase as a cross-linking agent for hardening the capsule wall.
U.S. Pat. No. 6,500,463 discloses embedding a liquid encapsulant component by admixing with at least one plasticizable matrix material, a substantially non-plasticizable matrix component, and a plasticizer, to obtain a formable, extrudable, cuttable mixture or dough.
U.S. Pat. No. 6,969,530 discloses a microcapsule comprising a loading substance, a primary shell, and a secondary shell, wherein the primary shell encapsulates the loading substance and the secondary shell encapsulates the loading substance and the primary shell, wherein the primary shell and/or the secondary shell comprises a gelatin having a Bloom number of less than 50.
U.S. Pat. No. 6,974,592 discloses a microcapsule, each comprising an agglomeration of primary microcapsules, each primary microcapsule having a primary shell and the agglomeration being encapsulated by an outer shell. Each shell material is made of first and second polymer components.
U.S. Publication No. US 2004/0017017 discloses microcapsules made by forming an emulsion of an oil component, an aqueous component, and a film forming component. The emulsion is homogenized, and pellets are produced by reducing the water content of the stabilized emulsion so that the film forming component forms a film around the oil droplets and encapsulates the encapsulant. The water content can be reduced by spray-drying.
U.S. Publication No. US 2004/0169298 discloses a microcapsule comprising an oil-based core material immiscible with water, and a shell material comprising gum arabic and an enteric anionic cellulose derivative. The method of making the microcapsule does not use either gelatin or an organic solvent.
U.S. Publication No. US 2005/0067726 discloses single and multi-core microcapsules having multiple shells, at least one of which is a complex coacervate of two components of shell materials. The core material can be a hydrophobic liquid such as various oils, the shell material can be formed from a first component which is preferably gelatine type A, and the second component is preferable gelatine type B, polyphosphate, gum arabic, alginate, carrageenan, pectin, carboxymethylcellulose, or a mixture thereof.
PCT Publication No. WO 97/48288 discloses an encapsulated material wherein the core comprises an encapsulatable material such as an oil, and the coating layer over the core comprises a protein having a mixture of hydrophobic and hydrophilic properties selected from the group consisting of isolated soy protein, whey protein isolate, caseinate and mixtures thereof.
Ijichi, K., et al., J. Chem. Eng. Of Japan, Vol. 30, No. 5, pp. 793-798 (1997) discloses microencapsulation of biphenyl using gelatin/acacia complex coacervation having multiple layers made by repeated complex coacervation.
It is one object of the invention to provide a microencapsulated oil product that can be incorporated into a food or beverage product to provide a nutritional benefit to the consumer, such as providing a source of essential fatty acids, amino acids, vegetable or animal derived protein, carbohydrates, vitamins, and minerals.
It is another object of the invention to provide such a microencapsulated product wherein the microcapsule walls are relatively strong and impervious to mechanical rupture.
It is another object of the invention to provide a method for making such a microencapsulated oil product.
It is yet another object of the invention to provide food and beverage products incorporating such microencapsulated oil products.